The £8m investment in NBNK by the major backer of Virgin Money came hours before the 5pm deadline on Thursday set by Royal Bank of Scotland for the 316 branches it is being forced to sell by Brussels in return for its £45bn taxpayer bailout.

Virgin Money is thought to be among those to have expressed an interest in branches, along with the venture capitalists JC Flowers, Nationwide building society and the private equity company AnaCap.

There was speculation NBNK could be used as a way for Virgin Money to gain a stock market listing if it was successful in bidding for the RBS branches up for sale. The decision by Ross to invest in NBNK means it will no longer be wound up and can renew its search for possible acquisitions.

Ross will be become chairman, replacing Lord Levene, a former Lloyd's of London chairman, while the chief executive, Gary Hoffman, who became chief executive of the Hastings insurance group last month, will also leave.